This invention relates to a reverse osmosis system and particularly to an integral disposable reverse osmosis unit which may conveniently be inserted into and removed from a system.
Brackish water has an unacceptable taste that can be remedied by water treatment processes such as reverse osmosis. Spirally wound, tubular, or hollow fiber reverse osmosis membrane modules are used for reducing the mineral quantity in potable water or in water used for preparing ice, beverages, etc. These modules are housed in permanent pressure vessels which may be made of PVC, stainless steel, or fiber reinforced plastic material. The reverse osmosis process requires a certain level of water pressure to push the water through the membrane, leaving the removed minerals on the surface of the membrane. The accumulated minerals are washed off the membrane by a reject or waste stream of water flowing at a fairly high velocity along the surface of the membrane. This basic requirement of water pressure and water flow can be met by line pressure existing in a water supply system or can be provided by a pump operating to provide such conditions. Higher water pressures result in larger flows through the membrane and also better rejection of unwanted minerals.
The modules contained in presently used pressure vessels slowly lose their effectiveness to remove minerals due to various chemical and physical aspects of mineral build-up on the surface of the membrane. When the flow through the membrane surfaces becomes too slow or too poor in quality for intended end use, the water flow is stopped usually with an appropriate valve ahead of the system, the pressure vessel is opened, and the used reverse osmosis membrane module is removed from the vessel and discarded. A new membrane module is inserted into the vessel, retaining means are fastened, the vessel is closed, and the valve is opened so that the required operating conditions can be reestablished.
The process of changing modules can be very messy and time consuming. In some areas under some operating conditions, the changing process may have to be done often, resulting in high maintenance costs. Additional difficulties are encountered when the devices are located and mounted in rather inaccessible places.
Accordingly it becomes appropriate to develop a reverse osmosis assembly in which an integral disposable reverse osmosis unit can be inserted in a head member and then be removed and replaced as a unit thereby avoiding a plurality of problems now commonplace with existing units.